Field of the Invention
The present invention relates to an organic light emitting display (OLED) device having improved durability, and a method for manufacturing the same.
Description of the Related Art
An OLED device is a self-light emitting display device that does not need a separate light source such as a backlight for a liquid crystal display (LCD). Thus, the OLED device can be lightweight and thin. Further, the OLED device has efficient power consumption because it is driven with a low voltage. Also, the OLED device has excellent color expression ability, a high response speed, a wide viewing angle, and a high contrast ratio (CR).
The OLED device includes a plurality of organic light emitting elements that respectively function as sub-pixels of the OLED device. The sub-pixels include a red sub-pixel that emits a red light, a green sub-pixel that emits a green light, and a blue sub-pixel that emits a blue light.
Each of the sub-pixels of the OLED device includes an anode, a common layer, an organic light emission layer, and a cathode. Anodes are separated from the respective sub-pixels, but a common layer is formed on the entire surface of a substrate so as to cover the anodes of the respective sub-pixels. An organic light emitting element emits light using holes supplied from the anode and electrons supplied from the cathode. Holes supplied to a specific sub-pixel can leak into another adjacent sub-pixel through the common layer. For example, holes supplied to a sub-pixel that emits a blue light may not move to an organic light emission layer of the sub-pixel that emits a blue light but, may leak into a sub-pixel that emits a red light or a sub-pixel that emits a green light through the common layer. Such a leakage current causes other nearby sub-pixels to emit light and change color characteristics of the OLED device.
In other words, the OLED device according to related art can have a leakage current that flows between nearby sub-pixels due to a common layer with a large thickness that is on a bank for separating the sub-pixels. As a result of the leakage current flowing between the nearby sub-pixels, the OLED device according to related art can have a light leakage problem.